Screen having parallel slots and method of making same

ABSTRACT

A screen having parallel slots therethrough comprises a plurality of rods supported in spaced parallel relation by transversely extending support members. The support members comprise spaced side walls having upper edges upon which the rods rest and arches extending upwardly between the rods to connect said side walls as one piece. The arches project into the region of minimum spacing between the rods and by engaging the sides of the rods accurately determine the spacing between rods. The arches are designed to snugly interfit the rods and cooperate with the rods to provide a smooth nonblinding screen surface.

United States Patent 1191 Bixby et a1.

[ SCREEN HAVING PARALLEL SLOTS AND METHOD OF MAKING SAME [75] Inventors:Leon C. Bixby, Clarks Green;

Anthony J. Martino, Carbondale, both of Pa.

[73] Assignee: Hendrick Manufacturing Company,

Carbondale, Pa.

22 Filed: Nov. 10, 1972 21 Appl. No.2 305,481

Related US. Application Data [63] Continuation of Ser. No. 35,186, May6, 1970,

abandoned.

[52] US. Cl. 209/395, 219/58 [51] Int. Cl B07b 1/12 [58] Field of Search219/58; 209/392, 393, 395, 209/400, 405-408, 98, 99; 210/499, 497.1, 497H, 498; 52/667, 668, 664, 669; 29/160,

[56] References Cited UNITED STATES PATENTS 1,769,128 7/1930 Fisher209/395 X 2,155,694

[ 1 Apr. 23, 1974 2,767,627 10/1956 Lynn 6161 52/668 3,023,904 3/1962Wehner 209/393 x 3,305,090 2/1967 Morawski et a1 209/407 x FOREIGNPATENTS OR APPLICATIONS 523,155 10/1953 Belgium 209/393 PrimaryExaminer-Tim R. Miles Assistant Examiner-R. .1. Hill Attorney, Agent, orFirmDybvig & Dybvig [57] ABSTRACT A screen having parallel slotstherethrough comprises a plurality of rods supported in spaced parallelrelation by transversely extending support members. The support memberscomprise spaced side walls having upper edges upon which the rods restand arches extending upwardly between the rods to connect said sidewalls as one piece. The arches project into the region of minimumspacing between the rods and by engaging the sides of the rodsaccurately determine the spacing between rods. The arches are designedto snugly interfit the rods and cooperate with the rods to provide asmooth nonblinding screen surface.

emm'gmma 1914 3805955 0 6 b 0 0 00 0 0} i-iffy? SCREEN HAVING PARALLELSLOTS AND METHOD OF MAKING SAME This is a continuation of applicationSer. No. 35,186 filed May 6, 1970, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to screens of the type used for drainage, sizing, dewatering andwashing of coal and ores, and for sand recovery and the like.

2. Description of the Prior Art It is known to fabricate screens for theabove described purposes by supporting rods in spaced parallel relationto define slots of predetermined size therebetween. In the knownconstructions the screen rods are equipped with depending flanges whichproject into slots of a transverse support member, the slots beingspaced along the length of the support member to accurately establishthe spaces or slots between the screen rods. For such construction, theflanges are made vertieally large enough to project downwardly throughportions of the support members a sufficient distance that transverselock pins can be passed through suitably located holes in the flangesand under the support members to lock the rods to the support members.For purposes of economy, the depending flanges are relatively thincompared to the width of the rods which define the screen slots and makeno contribution to the operation of the screen other than the functionof maintaining the desired spacing between the parallel rods of thescreen. The relative thinness of the depending flanges precludesreliable welding and hence the aforementioned lock pins are required inlieu of welding.

SUMMARY OF THE INVENTION In accordance with the present invention thedepending flanges which enter slots in transverse support members andthe lock pins which lock the depending flanges to the support membershave been eliminated. To accomplish this, the slots in the screensupport members are made wide enough to receive the screen rodsthemselves, rather than the depending flanges, and shallow enough thatthe screen rods continue to project at least to some extent above thesupport members. This construction allows the screen rods to be directlywelded for the support members and eliminates the need for the lock pinspreviously described. This construction also allows the slots which willreceive the lower surfaces of the screen rods to be conformed to suchlower surfaces, thus allowing a smooth and nonblinding screenconstruction. The particular construction to be described allows allwelding to occur in areas shielded from the active surfaces of thescreen and thus in areas not disruptive to the smoothness of the activescreen surfaces.

It is an object of the present invention to provide a new and improvedparallel slot screen construction.

Another object of the present invention is to provide a parallel slotscreen construction in which rods spaced apart to define the slots ofthe screen are seated in slots or cradles of a support member to whichthe rods may be directly welded.

A further object of the present invention is to provide transversesupport members for a parallel slot screen in which the support membershave slots or cradles to receive the screen rods and in which saidcradles are con- 2 toured to interfit the lower surfaces of the rodsreceived thereby.

Other objects and advantages reside in the construction of parts, thecombination thereof, the method of manufacture and the mode ofoperation, as will become more apparent from the following description.

DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a screenpanel constructed in accordance with the present invention.

FIG. 2 is a fragmentary plan view of a perforated sheet used toconstruct the screen support members of the FIG. I embodiment.

FIG. 3 is a fragmentary side elevation view of the FIG. 1 embodiment.

FIG. 4 is a perspective view of a first modification.

FIG. 5 is a fragmentary plan view of a perforated sheet member used toform the support members of the first modification.

FIG. 6 is a fragmentary side elevation view of the first modification.

FIG. 7 is a fragmentary side elevation view of a second modification.

FIG. 8 is a fragmentary perspective view of a perforated sheet used toform the support members of the second modification.

FIG. 9 is a fragmentary side elevation view illustrating an intermediatestage in the manufacture of the third modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, thereference number 10 in FIG. 1 designates a screen panel comprisingparallel rods 12 seated on transverse support members 14. While FIG. 1illustrates only two support members and seven screen rods, it is to beunderstood that the screen panel may be several feet long with thetransverse support members located periodically such as every threeinches along the length of the support rods and with the screen panelhaving a conveniently manageable width, such as 2 feet. The closestapproach between the rods 12, i.e., the slot dimension, is typically inthe range of one-eighth of an inch to 1 inch, or greater.

FIG. 2 illustrates a flat elongated metal sheet or plate 16 which hasperforations I8disposed at spaced intervals along the length thereof.Webs 20 separate the perforations 18. This sheet is in readiness forbending of the webs 20 along the longitudinal center of the sheet toform an elongate support member 14. The perforations 18 in the sheet 16are oblong and have a largest width dimension which is only slightlylarger than the diameter of the rods 12. The arcuate end margins 26 ofthese perforations are circularly curved at a radius only slightlylarger than the radius of the rods 12,

As previously indicated, the sheet 16 is bent along the longitudinalaxis thereof to form a support member 14. As this bending isaccomplished, the webs 20 which separate the perforations of the sheet16 are curved to form arches 22 which connect the upper portions ofdivergent imperforate side walls 24.

Those skilled in the art will recog ize that as this bending occurs, thelonger side margins of the perforations 18 will bend without spreadingas the arcuate end margins of the perforationsswing downwardly to formarcuate recesses at the upper edges of the walls 24 upon which thesupport rods 12 can rest. Since the were cut to substantially the samecurvature as the rods 12, the fit between the rods 12 and the margins ofthe perforations 18 will permit the rods 12 to fully close theperforations 18 to a degree of perfection limited only by inaccuraciesin the design of the somewhat elliptically shaped perforations 18.

As best appears in FIG. 3, the perforations 18 are so sized in relationto the amount of bending that occurs in forming the support members 14that only approximately the lower halves of the rods 12 enter theperforations 18. This assures that the rods 12 can be effective to closethe perforations 18. Thus, if appreciably more than one-half thediameter of the rods 12 were permitted to enter the perforations 18, thelargest dimension of the rods 12 would be below the apices of the arches22 so as to create openings between the arches and the rods 12 withinwhich material being screened could snag so as to clog or blind thescreen. It is also preferred that the perforations 18 be so sized withrespect to the arches 22 therebetween that the perforations will notreceive appreciably less than onehalf the diameter of the rods 12. Thisassures that the portions of the rods 12 which project above the apicesof the arches 22 will be spaced apart a distance at least as great asthe slot width and will not tend to snag or entrap material above thearches 22.

As appears in FIG. 3 the rods 12 are anchored to the support members 14by depositing a layer 28 of weld material on the undersides of the rods12 where these rods are exposed by the perforations 18. The weldmaterial is deposited initially as a blob of molten weld material and asthe blob is deposited on the exposed area of the rod 12, a current ofelectricity sufficient to locally heat the rod 12 to a high temperatureis passed through the area of contact with the rod 12. This heats therod in the area contacted by the blob of weld material to a temperaturesufficient to allow the weld material to flow throughout most, if notall, of the area of the rod 12 which has been exposed by the perforation18 through which the blob has been deposited. This flow of weld materialover the exposed surface of the rod 12 allows the weld material tocontact the edge margins of the perforations l8, i.e., the arches 22.This gives rise to two forces which allow the support members 14 toretain the rods 12. The first force is the retentive power resultingfrom a fusion of the weld material to the edge margins of theperforations. The second force resides in a type of interference fitthat forms between the weld layers 28 and the edge margins of theperforations. Thus, even should a fracture develop between a weld layer28 and the adjacent edge margin of a perforation 18, the rod 12 will notbe released from the support member 14.

This method of welding is desirable for the reason that the welding gunwhich is used to deposit the aforementioned blob of weld material is notbrought into contact with the support members 14. Should one attempt toweld directly to the support members 14, which are relatively thin incomparison to the rods 12, the welding operation could damage or destroythe strength of the support member 14. By depositing the weld materialonto the rods 12 rather than the support members 14, the welding can beaccomplished without damage to the structural strength of the supportmembers.

As clearly appears in FIG. 3, the side walls 24 for the support members14 diverge so as to readily admit a welding gun therebetween and willallow free travel of the welding gun longitudinally along the length ofthe support member. The described weld layers are easily deposited byassembling the screen panels upside down from what appears in FIG. 1 anddepositing the weld material inside of the support members 14.

While the embodiment of FIGS. 1-3 has been illus trated as havingperforations 18 which are initially somewhat elliptical so as to closelyfit the cylindrically curved undersides of the rods 12, those skilled inthe art will recognize that oblong perforations which have substantiallystraight margins at their longer sides and rounded end margins will inall but extreme cases produce an acceptable, although not perfect,nonblinding fit with the rods 12.

FIGS. 4, 5 and 6 illustrate a first modification of the presentinvention utilizing elongate support members 30 which have the generalshape of longitudinally truncated cylindrical tubes. A perforated sheet32 suitable for forming the support members 30 is illustrated in planview in FIG. 5. As clearly shown in FIG. 5, the perforations 34 in thesheet 32 have a greater elongation in the direction transverse to thelength of the sheet 32 than was required for the previously describedembodiment. The reason for this difference in the perforations is thatthe sheet 32 will be cylindrically curved whereas the precedingembodiment was arched to a substantially smaller radius of curvature.Due to the relatively gentle cylindrical curvature of the supportmembers 30, the perforations 34 require greater elongation so thatdesired proportions of the screen rods 12 can ultimately be receivedwithin the perforations 34. Construction lines 36 appearing in FIG. 5depict the approximate point at which the side margins of the sheet 32are folded back upon themselves so as to double the thickness at thesides of the support members 30. The construction lines 36 are locatedapproximately midway between the extreme side edges of the sheet 32 andthe cloest end margins of the perforations 34 so that when the sides ofthe sheet are folded back as described, the original side edges of thesheet 32 will be substantially tangent to the curved end margins of theperforations 34. When the sheet 32 is thereafter curved to the truncatedcylindrical shape appearing in FIG. 6, there is a double thickness ofthe sheet 32 in position to support the support rods 12 which will beplaced thereabove.

It will be understood that when the sheet 32 is formed to the truncatedcylindrical shape appearing in FIG. 6, the webs between the perforations34 will form arches 35. The construction of a screen panel with theresultant support members 30 is substantially as described in thepreceding embodiment. Thus, the rods 12 are merely seated between thearches 35 against the margins of the perforations 34 and affixed inposition by weld layers 38 which spread on the undersides of the rods 12to lock the rods 12 to the support members 30 as previously describedwith reference to the layers 28.

As described in reference to the FIG. 1 embodiment, the perforations 34have their end margins curved to substantially the curvature of the rods12 and have their longer side margins at a maximum separation which onlyslightly exceeds the diameter of the rods 12.

FIG. 7, 8 and 9 illustrate the second modification of 5 the presentinvention. In this modification an elongated perforated sheet 40 isfirst formed along its side margins to provide generally semicircularchannel portions 42 along the side margins. This leaves a perforated web44 between the channel portions 42. The web 44 is then curved about itslongitudinal axis to an approximate semicircular shape, to form asupport member 41, as appears in FIG. 9. The perforations 46 in the web44, which are approximately elliptical before the web 44 is curved,adjust to a proper shape as the web 44 is curved to receive or cradlethe support rods 12. After this curving, the sheet 40 has approximatelythe cross sectional shape illustrated in FIG. 9, with arches 45connecting the channel portions 42.

At this point in the screen construction, the support rods 12 may benested between the arches 45 and affixed thereto by weld layers 48placed thereunder in the manner previously described. With reference toFIG. 9, it will be noted that the condition of the support member 41 issuch as to allow ample room for insertion of a welding gun to apply thelayers 48.

A screen device of the type described with reference to FIG. 9 issuitable for many industrial purposes. However, where the screen willencounter exceptionally heavy duty, it is preferred to reinforce thescreen support members 41 with a sturdy beam. The construction of FIG. 9is well suited to heavy duty applications which will require a supportbeam. Thus, the channel portions 42 which curve outwardly, each from theother, form a somewhat circular opening which can receive a transversesupport beam such as the beam 50 illustrated in FIG. 7. The beam 50 isconveniently secured in position by first squeezing the channel portions42 one toward the other in a suitable press mechanism so as to partiallyclose the gap between their bottom edges. The beam 50 is then slidaxially between the channel portions 42. The edge gap between thechannel portions is not completely closed in the foregoing squeezeoperation so that sufficient heat can be applied to the beam 50 and tothe side edges of the channel portions 42 to weld the beam 50 to thechannel portions 42 as appears at 52 in FIG. 7.

While the drawing of the present application infers that the screenpanels are intended to be planar in the sense that the upper surfaces ofthe rods 12 would all contact a common plane, it will be apparent tothose skilled in the art that the rods 12 are readily curved in thedirection of their length and therefore the screen panel may becylindrically or otherwise curved as the user may require.

While the preferred embodiments of the present invention have beendescribed with reference to cylindrical rods 12, it is to be understoodthat the screen rods may have other cross sectional shapes such astriangular or square or rhombic. Such shapes are readily accommodatedwithin the teachings of the present invention by merely redesigning theperforations, particularly the end margins thereof, so that the webstherebetween, when ultimately curved or arched, will snugly fit thecontour of the screen rods, thus allowing the support members tocooperate with the screen rods to present a smooth nonsnagging surfaceto the material which will be moved across the upper surface of thescreen.

In the preferred constructions of the present invention the rods 12 andthe transverse support members may be fabricated from any materialsuitable to the job to be performed. As examples, the screen panels maybe made of steel, stainless steel, bronze and brass alloys, or aluminum.

Although the preferred embodiment of the device has been described, itwill be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts, the combination thereof and mode of operation, which generallystated consist in a device capable of carrying out the objects setforth, as disclosed and defined in the appended claims.

I-Iave thus described our invention, we claim:

1. In a screen device of the type comprising a plurality of spaced andgenerally parallel rods and a support member underlying said rods, saidsupport member comprising an elongate sheet member having spaced apartlongitudinal side edges and arched to a crest between said edges, saidcrest extending along the length of said sheet member, said sheet memberhaving perforations through its thickness at said crest, saidperforations spaced from said side edges and spaced apart along thelength of said crest, there being one perforation for each rod, saidrods extending transverse to the length of said sheet member, each rodcrossing over a different one of said perforations and cradled betweenmargins of the perforation crossed thereby which are spaced apart alongthe length of said crest, the improvements wherein said rods arecylindrical rods, the diameter of each rod exceeding the thickness ofsaid sheet member, and wherein each rod is secured to said sheet memberby a single weld layer fused to said rod, said weld layer extendingunder said rod to contact and interference fit each of the spaced apartmargins between which said rod is cradled.

2. The screen device of claim 1 wherein said perforations are sized toadmit approximately one-half of the diameter of said rods below theelevation of said crest, the remaining portion of the rod diameter atsaid crest projecting above the elevation of said crest.

3. The screen device of claim 1 wherein the portions of said sheetmember disposed between said perforations and said side edges comprisegenerally confronting walls disposed below said rods, said walls curvedeach away from the other to define a generally circular openingextending along the length of said support member and under said rods.

4. The screen device of claim 3 wherein said sheet member is folded backupon itself at each of said walls to double the thickness of said sheetmember below said rods.

5. In the method of making a screen device, the steps comprising:cutting a plurality of spaced apart perforations through the thicknessof a generally flat sheet member, bending said sheet member about anaxis passing through all of said perforations whereby the margins ofsaid sheet member surrounding said perforations define recesses in theconvex side of said sheet member, positioning a plurality of cylindricalrods, one for each perforation, adjacent and across the convex side ofsaid sheet member and against said margins to close said perforations,the diameter of each rod being greater than the thickness of said sheetmember, depos- 3 8 O5 ,9 5 5 7 8 iting weld material onto each of saidrods from the conof the rod closing the perforation through which thecave side of said sheet member through the perforation weld material hasbeen deposited, thus to contact a closed by said rod, and heating eachof said rods where margin of said sheet member surrounding suchperforacontacted by said weld material to a temperature suffitron. cientto allow the weld material to flow across the area 5 ,HIJNITED STATESPATENT {OFFICE CERTIFICATE OF CORRECTION Patent No. 2 ,8 5,955 v DatedApril 23. 197 1 Inventofls) arti no It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown below:

In Column 1, line A 7, "for'" should read -to o (page 3, ine 40f thespecifications) Column 5 line 33, eupport" should readenpporting- (page11, line 7 of the specifications) IN THE cLAIMs Column 6; line 23,,insert- -sideafter "saidfi (Page 1 (of Amendment.) line 5) eigned msealed this 19th day of November 1974a (SEAL) v Attest': v

MCCOY M, GIBSON JR Y v c. MARSHALL DANN Attegting Officer Commissionerof Patcnts FORM Do-1050 (0-69) USCOMM-DC soavsmeg a [1.5. GOVERNMENTFRlNTlNG OFFICE: I969 3$6-33l MIHINETED STATES. PATENT FJZOFFICECERTIFICATE- OF CORRECTION Patent No. 3 5955 A t d April 23, 197 1Inventor(s) It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

In Column 1, line 47, "for" should read -to -w (page 3, line 4 of-thespecifications) Column 5, line 33, "support" should reaG- eu ppQPtingY--H (page 11, linev 7' of the specifications) IN THE VCLAIMS Column 6,line. 23, insert- --side---after' "said".

(Page 1 (of Amendment) line 5) Signed end sealed this 19th day ofNovember 1974 (SEAL),

Attest: v

Mecor M. GIBSON JR 7 N c. MARSHALL DANN Attesting Officer 5 Commissionerof Patents FORM 30-1050 (0-69) USCOMM-DC 603764 69 U.5. GOVERNMENTPRINTING OFFICE: I9, 0-366-334

1. In a screen device of the type comprising a plurality of spaced andgenerally parallel rods and a support member underlying said rods, saidsupport member comprising an elongate sheet member having spaced apartlongitudinal side edges and arched to a crest between said edges, saidcrest extending along the length of said sheet member, said sheet memberhaving perforations through its thickness at said crest, saidperforations spaced from said side edges and spaced apart along thelength of said crest, there being one perforation for each rod, saidrods extending transverse to the length of said sheet member, each rodcrossing over a different one of said perforations and cradled betweenmargins of the perforation crossed thereby which are spaced apart alongthe length of said crest, the improvements wherein said rods arecylindrical rods, the diameter of each rod exceeding the thickness ofsaid sheet member, and wherein each rod is secured to said sheet memberby a single weld layer fused to said rod, said weld layer extendingunder said rod to contact and interference fit each of the spaced apartmargins between which said rod is cradled.
 2. The screen device of claim1 wherein said perforations are sized to admit approximately one-half ofthe diameter of said rods below the elevation of said crest, theremaining portion of the rod diameter at said crest projecting above theelevation of said crest.
 3. The screen device of claim 1 wherein theportions of said sheet member disposed between said perforations andsaid side edges comprise generally confronting walls disposed below saidrods, said walls curved each away from the other to define a generallycircular opening extending along the length of said support member andunder said rods.
 4. The screen device of claim 3 wherein said sheetmember is folded back upon itself at each of said walls to double thethickness of said sheet member below said rods.
 5. In the method ofmaking a screen device, the steps comprising: cutting a plurality ofspaced apart perforations through the thickness of a generally flatsheet member, bending said sheet member about an axis passing throughall of said perforations whereby the margins of said sheet membersurrounding said perforations define recesses in the convex side of saidsheet member, positioning a plurality of cylindrical rods, one for eachperforation, adjacent and across the convex side of said sheet memberand against said margins to close said perforations, the diameter ofeach rod being greater than the thickness of said sheet member,depositing weld material onto each of said rods from the concave side ofsaid sheet member through the perforation closed by said rod, andheating each of said rods where contacted by said weld material to atemperature sufficient to allow the weld material to flow across thearea of the rod closing the perforation through which the weld materialhas been deposited, thus to contact a margin of said sheet membersurrounding such perforation.